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Resource summary

Stress-related illness
and the immune system

1 the immune system

1.1 the immune system consists of a
complex network of cells and
chemicals and protects us against
diseases and illnesses. The immune
response is triggered by antigens-
substances that the body recognises
as foreign. Some antigens, such as
pollen or house dust, can be
harmless to some people but provoke
allergic responses to others. Antigens
can also be carried on the surface of
harmful disease-causing pathogens,
such as viruses, bacteria and fungi

1.2 white blood cells, known as lymphocytes and phagocytes, are particularly
important in the immune response and protect us in 3 different ways

1.2.1 1. non-specific immunity

1.2.1.1 phagocytes, such as macrophages, surround and ingest
foreign particles. Macrophages scout for pathogens and
alert other macrophages to an invasion when it detects
them. They can also alert lymphocytes called helper T
cells

1.2.2 2. cell-based immunity

1.2.2.1 T cells, made in the
thymus gland, find and
destroy cells that they
identify as foreign or
infected. They activate
killer cells known as
cytotoxic T cells, which
destroy infected cells and
activate lymphocytes called
B cells

1.2.3 3. antibody-based immunity

1.2.3.1 B cells, made in the bone
marrow, attack invading
substances in the
bloodstream before
infections even reach
cellular or tissue level. The B
cells form plasma cells,
which make antibodies that
bind to viral antigens and
slow them down so that they
can be destroyed more
easily

2 Stress-related illness

2.1 our bodies are designed to react to stress but
not for long periods. Immune system
functioning can be reduced by both acute and
chronic stress, although chronic stress is
more dangerous

2.2 acute stress and the immune

2.2.1 as the acute stress response is designed to be short-term the immune
system should not be dangerously weakened by short periods of stress.
However, even short-term stress can cause some problems

2.2.2 in a natural experiment
Kiecolt-Glaser et al. (1984)
monitored T cell activity in the
blood of 75 medical students
one month before, during, and
one month after their final
exams and found that it was
reduced

2.2.2.1 this means that immune responses could also be reduced,
leaving the students more vulnerable to illness

2.2.2.2 in evaluating these
findings, there are several
points to make

2.2.2.2.1 medical students might be unlike other students,
limiting the generalizability to other groups

2.2.2.2.2 Kiecolt-Glaser et al. (1984, 1991), found further support for
their conclusions in carers of people with Alzheimer's
disease and in women going though divorce

2.2.2.2.3 further evidence was provided by Marshall
et al. (1998), who found that short-term
stressors, such as exams, can slow
recovery by reducing the production of
cytokines, which promote wound healing

2.2.2.2.4 acute stress alone may not explain the findings, as it was also
found that the presence of co-existing long-term stressors, such
as loneliness, could exacerbate the effects of acute stress

2.3 chronic stress and the immune system

2.3.1 interpersonal conflict

2.3.1.1 Cohen (2005)
showed that
couples in conflict
that had lasted for
more than a
month were
especially
vulnerable to
succumbing to
infection when
exposed to an
infectious agent

2.3.1.2 Kiecolt-Glaser
(2005) supported
the idea that
immune responses
are reduced by
showing that blisters
on the arms of
couples healed
more slowly after
conflicting
discussions
compared to after
supportive ones.

2.3.1.3 others, such as Mayne et al. (1997), have
suggested a gender difference in that women in
conflicting couples show stronger immune
suppression

2.3.2 death of a close relative

2.3.2.1 Gerra et al. (2003) showed
lower natural killer cell and
lymphocyte activity in
bereaved people compared
with matched controls. This
difference was still present
40 days after the
bereavement and
persistent in some
individuals for months

2.3.3.1 Kiecolt-Glaser et al. (2000) found that
long-term care of a dependent relative was
associated with lower levels of killer cell
activity and poor resistance to viral infection
in caregivers compared with matched
non-caregivers

3 Evaluation of studies of the
effect of stress on the
immune system

3.1 good experimental suppot

3.1.1 there are many good-quality,
experimental studies (as outlined
above) that give clear evidence
for changes in immune system to
both acute and chronic stress

3.2 reductionism

3.2.1 to reduce the impact of stress to something that is purely physiological/ biological
ignores the whole person and the sociocultural context in which they live. Many
other factors that are difficult to control in research could be involved, such as
depression, anxiety, level of social support and cultural tolerance of weakness

3.3 individual differences

3.3.1 some of the studies described here have suggested that
variables such as gender might mediate responses to stress.
In addition, age or personality factors could make people vary
in vulnerability and would need to be controlled if the effects of
stress are to be clearly understood